Who was exclusively feeding the baby with breast milk? It's possible t…

Who was exclusively feeding the baby with breast milk? It's possible to prolong lactation if the baby doesn't take the breast. Could there be some nuances in breastfeeding? A breast pump doesn't fully express milk like a baby would suckle, I'm afraid that it might disappear over time as the baby is not sucking on it. I am worried about my low milk supply and all the rules for increasing lactation don't help.